The present invention relates to surface working apparatus and in particular, but not exclusively, to surface working apparatus having a surface working head arrangement with a plurality of surface working elements depending therefrom, which elements are particularly adapted for an operation such as burnishing and which elements particularly exhibit relatively limited flexibility/compressibility.
Various versions of surface working apparatus are known which can be operated for tasks such as burnishing and wherein the surface working elements comprise pad members which exhibit a relative lack of compressibility/flexibility when compared with other surface working elements such as brushes etc.
In order to provide an efficient surface working apparatus, a surface working head arrangement is currently provided with has a plurality of such pads, or other surface working elements, depending therefrom such that a plurality of pads or other elements are operated simultaneously to achieve the surface working action required, be it burnishing, scrubbing, cleaning or polishing etc.
However, such apparatus is commonly required to operate over a variety of surfaces offering different characteristics and, in particular, different degrees of uniformity. For example, while some surfaces to be worked may comprise a relatively level and smooth surface, other surfaces, particularly those prone to excessive wear or potential damage, and/or older surfaces, may exhibit undulations such that a relatively uneven surface is presented for working.
Known surface working apparatus is disadvantageously limited in that the quality of surface working that can be achieved is limited since the plurality of surface working elements cannot adequately compensate for such uneven surfaces.
The present invention therefore seeks to provide a surface working apparatus having advantages over known such apparatus.
According to one aspect of the present invention there is provided surface working apparatus comprising a surface working head arrangement having a frame member and including a plurality of surface working members arranged to depend therefrom in the direction of the surface to be worked, wherein each of the said plurality of surface working members is mounted resiliently relative to the said frame member by one of a plurality of respective resilient mounting arrangements.
The independent, and resilient mounting of each of the surface working members, e.g. a pad member, advantageously allows for each of the surface working members to move relative to the frame member so as to compensate for undulations or unevenness in the surface being worked. Thus, whilst the frame member may be held at a constant level, determined by the pressure to be applied, over the undulating surface, the respective surface working members can move relative to that level so as to follow independently the undulations of the surface.
Drive means are associated with the surface working apparatus for driving the surface working members and such drive means are advantageously mounted to the frame member and the surface working members then resiliently mounted to the drive means. Most appropriately, a corresponding plurality of respective drive means is also provided on the surface working apparatus.
Preferably, the resilient mounting arrangement includes a compression spring which can be further advantageously arranged to be compressed to substantially half its length when the surface working head arrangement is exhibiting the particular required force on the surface being worked. Thus, the characteristics of the compression spring are advantageously matched to the particular nature of the surface working member associated therewith, be it a pad member, brush member or other appropriate member.
The resilient member is advantageously located between the drive shaft of the drive means and a surface working member drive adaptor means. Further, a drive motor adaptor is drivingly located between the motor drive shaft and the resilient member.
Preferably, the surface working drive adaptor means includes a hollow cylindrical housing member for receiving one end of the motor drive shaft adaptor.
The resilient means is then advantageously located within the cylindrical housing for contact between a lower surface thereof and a lower surface of the motor drive shaft adaptor.
Preferably, the resilient mounting arrangement is arranged to be selectively operative dependent upon the pressure to be exerted through the surface working head arrangement and to the surface to be worked. This is a particularly advantageous feature since, when pressure levels exceed those that might otherwise damage the resilient member of the resilient mounting arrangement, the further biasing of the resilient member is prevented so as to prevent damage thereto during the further increase in pressure to be applied to the surface. Thus, as the pressure is increased above the aforementioned threshold level, pressure is no longer applied by way of the resilient member of the surface working head arrangement.
The selective operation is achieved through movement of the resilient member within the mounting arrangement and into, and out of, a position in which it can be influenced by increases/decreases in pressure.
The resilient means advantageously moves out of its operative position, i.e. a position in which it can be further compressed, once the pressure applied through the surface working head arrangement exceeds a certain, and in particular predetermined, level.
Advantageously, the resilient mounting arrangement includes a housing provided with an engagement formation which is arranged to be engaged so as to prevent further biasing of the resilient member as the pressure to be applied to the surface increases.
The resilient member advantageously comprises a compression spring which can be arranged to be compressed to substantially half its length when the required pressure is to be applied to the surface by way of the surface working head arrangement.
Further, the aforementioned engagement formation can advantageously comprise a shoulder portion arranged adjacent the resilient member and, insofar as the housing includes a bore portion, the engagement formation can advantageously comprise an annular shoulder member which can further be in the form of an annular shoulder surrounding a well, or a cylindrical recess portion.
Advantageously, the housing arrangement is arranged for providing a driving connection to a drive member extending from a motor arrangement for the surface working member and, in particular, the resilient member is arranged to contact the underside of the aforementioned driving member.
Further, the resilient member may be associated with a contact plate for contacting the aforementioned driving member.
Yet further, the undersurface of the driving member which is arranged to contact the resilient member by way of the aforementioned contact plate, or otherwise, can advantageously be provided with a chamferred, partially convex, or part spherical surface which serves to assist with a gimbal-like movement of the housing member relative to the driving member extending from the motor.
With regard to a further advantage, the housing member is provided with a resilient clip means serving to retain the driving member extending from the motor arrangement within the housing.
Advantageously, the driving member has an engagement formation arranged to receive the clip means so as to prevent its removal from the housing. The aforementioned engagement formation of the driving member can advantageously be in the form of a shoulder portion of the driving shaft.
Advantageously, the transverse cross section of the driving shaft comprises a polygon and, in particular, a hexagon. In particular, it may comprise a star shape or an appropriate form of scalloped hexagon.
In any case, the transverse cross-section advantageously exhibits corner regions and a recess can be formed in a side wall portion of the bore that receives the driving member so as to guide and retain operative movement of the clip in the region of the shoulder portion of the driving shaft.
The clip means is advantageously arranged to be deformed so as to allow for entry/exit of the driving member relative to the housing and, in particular, it is the angled side walls defined by the hexagonal cross-section that serve as ramp means for at least a portion of the clip means so that, as the aforesaid portion is moved along the ramp means, the clip means is deformed outwardly relative the centre of the driving member so as to allow for its removal from the housing.
The present invention also advantageously provides for a surface working device such as a pad or brush which can be employed in apparatus as defined above.
Thus, in accordance with another aspect of the present invention there is provided a surface working device comprising a support plate from which a surface working element is to depend from a lower surface thereof, said support plate including an upper surface which has a central region with a recess provided therein for the receipt of a drive member for rotating the device, wherein the recess includes a formation for receiving a resilient member intended for engagement by the drive member.
The formation provided in the recess advantageously serves to engage at least one portion of the resilient member such that another portion of the resilient member can be engaged by the drive member so that relative movement between the drive member and the support plate can be achieved whilst deforming the resilient member.
Advantageously, the said central region comprises an upstanding region with the recess provided therein. If required, the recess can therefore be provided within the upstanding central region so that the depth of the recess is not dependent upon the thickness of the support plate.
In particular, the upstanding region can comprise an upstanding cylindrical member having the recess formed therein and which is coaxial with the support plate.
While the support plate can itself be provided with formations for receiving the portion defining the said central region, the central region defining the recess can advantageously be formed integral with the support plate.
In one particular embodiment, the said recess comprises a substantially blind bore which may advantageously have an end surface exhibiting a generally concave profile.
The generally concave profile can advantageously serve to enhance any gimballing effect that may be required between the drive member and the device.
Preferably, the said formation for receiving the resilient member can itself comprise a further recess which, advantageously, can be formed coaxially with the said recess formed at the central region of the support plate.
The said further recess can advantageously be in the form of a substantially blind bore. In any case, the depth of the recess is chosen so as to determine the maximum deformation of the resilient member.
Advantageously, the resilient member can comprise a compression spring which is arranged to extend coaxially with the said further recess and the recess provided in the said central region of the support plate.
In one particular embodiment, the recess provided in the central region of the support plate has a substantially hexagonal lateral cross-section and is arranged for receiving a substantially hexagonal head of the drive member.
The depth of the recess formed in the central region is advantageously formed to be at least slightly greater than the depth of the head of the drive member. In this manner, the said central region of the support plate can be advantageously provided with a spring retaining clip which requires deformation to allow the drive head into, or out of, the recess formed within the central region of the support plate.
The present invention is particularly advantageous when embodied with a surface working head arrangement exhibiting at least three surface working members which, when viewed from above, can be provided in a triangular formation on the frame of the surface working head arrangement. As mentioned before, such surface working members advantageously comprise pads, which, in particular, are arranged for burnishing of the surface to be worked.
In the aforementioned manner, the frame member of the surface working head arrangement can comprise a laterally extending deck member having a plurality of drive motors extending from the upper surface thereof and a plurality of respective surface working members extending from the lower surface thereof aligned with the motors.
Advantageously, the surface working apparatus Comprises a machine frame supporting a motor-driven surface working head arrangement, means for selectively varying the pressure exerted by said head arrangement on said surface, and means for selectively varying the speed at which said head arrangement is driven by said motor.
Preferably, the surface working head arrangement is adapted for the releasable mounting of a variety of surface working elements. Further, the surface working head arrangement can be arranged for releasable mounting of a plurality of surface working members each having different surface working characteristics.
The means for selectively varying the pressure exerted by the surface working head can be arranged to alter said pressure in response to use of said surface working head means exhibiting different working characteristics.
Further, the means for selectively varying the speed at which said head arrangement is driven by said motor may be arranged such that said speed can be altered in response to use of said surface working head means exhibiting different characteristics.
Advantageously, the apparatus includes actuator arrangement comprising spring means mounted to act as suspension means including means for biasing the surface working head arrangement towards a surface to be worked, tensioning means for tensioning the spring means so as to set the pressure of the surface working head arrangement and wherein the spring means is selectively adjustable by the tensioning means over a continuous range to provide a required bias towards the surface.
The tensioning means may include means for controlling the tension in the spring means so as to vary the bias of the surface working head arrangement. Also, the actuator arrangement can be arranged to compress the spring means.
The apparatus may further include biasing means acting between the frame and the surface working head arrangement to apply to the surface working head arrangement a selectable bias towards the surface to be worked and mounted to act as suspension means between the frame and the surface working head arrangement, means for monitoring and/or measuring the applied working pressure, means for displaying an indication of the measured working pressure, means for operator entry of a desired working pressure for the surface working head arrangement and, comparator means for comparing the operator input pressure to the measured pressure and for generating a control signal in response to the difference between the desired pressure and the measured pressure and means for applying the control signal to the pressure applying means.
The means for selectively varying the pressure applied to the surface by said surface working head arrangement can comprise biasing means acting between the frame and said surface working head arrangement and comprising an actuator having a first member, and a second member extendible therefrom and which actuator is further preferably operable manually, hydraulically or electrically.
The biasing means advantageously comprises a spring means which may further include at least one spring device acting between a portion of the actuator and the surface working head arrangement. The spring device can comprise a sleeve secured to said portion of said actuator means, a rod having an inner end slidable within the sleeve, the rod projecting from the sleeve to the surface working head arrangement, and a spring located within the sleeve engaging the inner end of the rod.
Further, the apparatus can include an actuator arrangement for raising and lowering the surface working head arrangement and mounted between the frame and the surface working head arrangement, and means operatively connected to the surface working head arrangement and arranged to at least partially counteract the force to be exerted via the surface working head arrangement on the surface, and so as to control the pressure exerted by the surface working head arrangement on the surface to a range which includes zero pressure to a pressure corresponding to the weight of the surface working head arrangement.
In particular, the means for counteracting the force exerted on the surface working head arrangement by the actuator can comprise counterbalancing means.
The means for counteracting can comprise resilient means operatively connected to the surface working head arrangement.
Advantageously, the resilience of the resilient means is selectively variable.
Preferably, the resilient means comprises at least two relatively moveable members which are arranged to be relatively movable in a resilient manner. The resilient means advantageously comprises a cylinder and piston arrangement.
The resilient means can then comprise a gas strut arrangement.
Alternatively, the resilient means can comprise spring means.
As a further alternative, the means for selectively varying the pressure exerted by the surface working head arrangement comprises an elongate balance beam pivotally connected to the frame and connected at one end to the actuator for movement therewith, and at the other end having a counter balance mounted thereon.
The means for selectively varying the speed at which the head arrangement is driven can comprise a selective plurality of gear arrangements having gear ratios determined on the basis of the working operations required.
The gearing arrangement preferably comprises respective pairs of gears in constant mesh and means for selecting one of said pairs for delivering the upward drive from said gearbox.
The means for selecting said one of said pairs advantageously comprises clutch means in the form of dog-clutch means.
The apparatus can further include control means comprising a solenoid actuator arranged to be retained in its two or more possible operative positions by solenoid locking means.
Preferably, means for controlling switching in the gearbox and which is associated with the means for selecting the pressure applied by way of the surface working head arrangement can be provided so that the switching of the gearbox is achieved in response to the selection of particular pressure values either above or below one or more threshold values or the selection of specific values.
Preferably, the apparatus has a control arrangement arranged such that the selection of any particular pressure value or range is responsive to switching of the gearbox. Further, the gearing arrangement advantageously comprises a first gear pair with a 1:1 ratio and a second gear pair with a 5:1 ratio.
Control means can be provided to inhibit the change in the gearing mechanism while the motor is driving the surface head arrangement. In particular, the control means is arranged to limit the pressure that can be applied by way of the surface working head arrangement once the high speed gear ratio is selected.
Advantageously, the apparatus comprises a combined floor scrubber/burnisher machine.